Our aims are: 1. To determine if DNA of E. coli is attached to the membrane at the site of origin of chromosome replication. If this can be shown to be the case, we will study the nature of the bonds between this region of the DNA and the membrane, the time and mode of inception of these bonds, and, possibly, the regulation of their formation. 2. To determine if other sites of attachment of the E. coli chromosome to the membrane are at special regions of DNA denaturation. We will attempt to assess physiological significance of these sites by relating their number to defined physiological changes (i.e., different rates of growth). 3. To determine the mode of participation of different portions of the membrane of E. coli in the morphogenesis and extrusion of bacteriophage fl.